Tabletop Roleplaying Games.
I bought Mutant Year Zero in 2015 thinking "Ah, this will give me countless hours of play! I can make my own adventures and stuff!"
Now, my shelf is buckling after trying a hundred different games and supplements, and getting addicted to pretty books.
Currently, my favorite game of all time is Delta Green. Investigative horror mystery. Amazingly horrific scenarios (adventures) with True Detective season one level of masterful writing.
I love how TTRPGs are the model for having a quality product means people will buy it. It's not difficult to pirate everything, and many systems are just flat out free. And yet I buy most of it.